Trying to get on plane

[Flygaff]

Here's what I got. My Boat is a 2010 G3 Angler 185F. 1700 pound hull. When I purchased the boat a couple of months ago it had a pair of 2010 Yamaha 8 HP engines mounted on it. I removed the 8 HP Yammis and replace them with a pair of 2021 Suzuki 9.9s  upgraded to 20 HP each. I would have thought I would easily get up on plane with twin 20S. I have gone thru a few prop combinations. first i tried the supplied 9 1/4 x 5.5 Pusher props. RPMs hit the limiter quickly at 6.5 MPH. Next a pair of 9 1/4 x 11. 4200 RPMs at 9.5 MPH. Next I went down to 9 1/4 x 8. 5850 RPM at about 10 MPH. I then went to 9 1/4 x 7 4 Blade prop. RPMs hit limit at 7.1 MPH. The memory in the sonar unit says this boat went up to 18 MPH with the twin 8s. The strange thing about the boat is it had approx 320 pounds of weights in the transom well. I have not put them back in yet, but I can't understand what they would do to get the boat on plane. any thoughts?

Thanks

[lost a lure]

I have a 1200 lb boat with 50 hp. 25-27 mph. Sounds underpowered.

[Decoy Hound]

I would say still underpowered as well.

[Fishnatzee]

I have a 60 hp yamaha on my G3 17 guide and it gets up on plane, but it doesn't have a great hole shot due to being a four stroke. I think you are way under power for a boat that size and weight. What does the manufacturer recommend for maximum HP? 

[whaler1]

Have you tried with someone (weight) on the bow?

[Flygaff]

when I walk up to the bow when running the speed jumps up to 11.4.  i know I'm close to plane. I wonder how it went 18 with twin 8 hp motors

If I can just get it near 18/20 I will be satisfied. I am thinking about two hydro foils

[Misdirection]

First off, hull speed on your boat is about 6.7 mph, so anything beyond that the boat is planning. But you lack the hp to push it faster. I seriously doubt that twin 8 hp motors pushed it any faster than what your already seeing. And I don't think adding hydrofoils is going to do much else.

The one thing that may help is making sure your cavitation plate is even with the bottom of your bloat. If its below, see if you can raise them up a hole or two.

But overall, your simply under powered.



Sent from my SM-S901U using Tapatalk

[Flygaff]

1 hour ago, Misdirection said:

First off, hull speed on your boat is about 6.7 mph, so anything beyond that the boat is planning. But you lack the hp to push it faster. I seriously doubt that twin 8 hp motors pushed it any faster than what your already seeing. And I don't think adding hydrofoils is going to do much else.

The one thing that may help is making sure your cavitation plate is even with the bottom of your bloat. If its below, see if you can raise them up a hole or two.

But overall, your simply under powered.



Sent from my SM-S901U using Tapatalk
 

I have the cav plates 1/4 inch above the bottom. i can't figure out why the dealer placed 320 pound of extra weight in the engine well. I my put it back and see what happens. 

[Bozeman Bob]

Adding weight has never helped any boat go faster , period . How do you know for sure what motor or motors where on it when it hit 18 mph ? Does the display say what motors are on it for different speeds ? Lose as much weight as you can , foils will cause more drag because your UNDERPOWERED for the umpteenth time.

[Flygaff]

This was a dealer rigged boat with the twin 8s. The only engines ever on the boat. I just don't know why they would have added 320 pounds to the stern. The logs in memory on the hummingbird says on multible routes 15 MPH and up the 18. Strange. I will try distributing the weight and trying again. I do know i'm underpowered. just trying to squeeze a little more speed out of her

[jeb1340]

Leaving the unit on and driving it on the trailer? I know where we launch, we load the boat on and then drive 1/4 mile to unload everything and secure the boat. Numerous times I left electronics on for that ride. It would probably be right around those speeds too.

[J.D.]

Checking the original catalog for specs., my 1996 17 ft. Starcraft hull weighs in at 1000 lbs. My 90 hp. Mercury 2-stroke weighs 303 lbs.

 

That's a dry weight of 1,303 lbs. pushed by 90 hp. The boat is rated up to 125 Hp. I run fully loaded with 2 people and gear at 40 mph. with a 19 pitch aluminum prop. It sounds like your weight to horsepower ratio is way off.

Edited September 2, 2022 by J.D.

[Fishinjohn]

I must be missing something here... lol..

I have an alumacraft 185 with a 140hp on it... its rated for a 175hp..

I've personally never heard of anyone putting twin 9.9 kicker motors on a boat that size for its main propulsion...

I have a 9.9 on the back of mine STRICTLY for trolling... I can tell you 100% that with will NEVER put me on plane...

Even 2 of them will never put me on plane...

I'd put a minimum 90hp on that thing.. you'll plane just fine..

[Flygaff]

Yea, the hull weighs 1700, 2 engines at 120 each and four group 31 AGMs. Lots of weight. I will keep messing with it. I will get it going a bit faster. I just need 3-4 MPH to be satisfied

[sherman brown]

what hp is the hull rated for. I believe you would be so much better off if you just sold the 2 small motors and got one larger hp motor. if we didn't live so far apart, I have a great running 70 hp Johnson, I could give you a great price on. my 115 wasn't running and I didn't know if it could be fixed so I bought the 70 hp to replace it. but the 115 got fixed and I have no need for the 70.

[Flygaff]

Lake restrictions of 9.9 hp. They don’t seem to care how many you hang on the transom. I upgraded them to 20 hp each. I am keeping my eyes open for a 90 or 115. The boat could be ordered with a 90 or 115 and the hull is rated to 200

[jeb1340]

Are you keeping the boat on that lake or primarily fishing someplace else? 

[Fishinjohn]

38 minutes ago, Flygaff said:

Lake restrictions of 9.9 hp. They don’t seem to care how many you hang on the transom. I upgraded them to 20 hp each. I am keeping my eyes open for a 90 or 115. The boat could be ordered with a 90 or 115 and the hull is rated to 200

MOST LAKES that have a HP restriction around me, allow the boat on the water no matter how big main motor is as long as it's up in the air out of the water...

They dont WANT YOU on plane.. lol

Even if its 2 or 3 smaller motors

[Flygaff]

7 hours ago, jeb1340 said:

Are you keeping the boat on that lake or primarily fishing someplace else? 

I go to other lakes and rivers. That's why I would like it to go a bit faster

 

[Flygaff]

Well the twin 9.9/20 did not work. I just mounted a Suzuki 140. Keeping one 9.9 for trolling. I have not run the boat yet. My guess is I will be just over 40 mph give or take. I will know in a few days. Now I wonder if I can run this 15-20 miles off the beach. I have a lot of offshore (75+miles) with my now gone 25 center. Have to check my fuel burn. It hold 35 gal. Looks like I wont get to the tuna, but sharks should be in range.

[sherman brown]

16 hours ago, Flygaff said:

Well the twin 9.9/20 did not work. I just mounted a Suzuki 140. Keeping one 9.9 for trolling. I have not run the boat yet. My guess is I will be just over 40 mph give or take. I will know in a few days. Now I wonder if I can run this 15-20 miles off the beach. I have a lot of offshore (75+miles) with my now gone 25 center. Have to check my fuel burn. It hold 35 gal. Looks like I wont get to the tuna, but sharks should be in range.

you shouldn't have any problems getting out that far with a 35 gallon tank. I fish Erie's central basin with a 21' glass cobia with a 350 Vortec 315 HP Mercruiser replacement motor with an aluminum high rise and a double pump holly 4 barrel 600 carb. I started out at 6:00 am in the morning and have gone out 18 to 20 miles then trolled until around 3 pm then made it back in running medium speed in rough water and it used less than 25 gallons to fill it back up. with a 35 gallon tank on a calmer day where you could stay on plane, you would be able to go even farther and not use 35 gallons. but when we would come back in rough water we would only be able to run about 15 MPH and that drank the gas.

[Flygaff]

Can’t wait to get out there. Our striped bass fishing gets underway in a few weeks. I just troll around the bay for them. I think I will be able to troll all day for them for about ten gallons of fuel. I hate to drop my new boat into to saltwater buts it’s gotta happen some day

[sherman brown]

1 hour ago, Flygaff said:

Can’t wait to get out there. Our striped bass fishing gets underway in a few weeks. I just troll around the bay for them. I think I will be able to troll all day for them for about ten gallons of fuel. I hate to drop my new boat into to saltwater buts it’s gotta happen some day

you want to be sure to wash the trailer as well as the boat with lots and lots of fresh water. then put a set of good muffs that puts water in from both sides and run the motor until it gets warmed up so it washes the whole system out. and don't be afraid to open the water up on high. i have always used high pressure on the hose. it doesn't get near the pressure as running down the lake at WOT.

[Flygaff]

Thanks, I ran the boat with the 140 on it for the first time yesterday. 34/35 mph. I thought it would run a bit faster. I only ran it for a few minutes cause I was on a 10 hp lake. I think with playing with the trim and a little weight distribution I believe I may gain a few more mph. I was at 5900 rpm. Mace is 6300. A balancing act for sure. 

[JLK]

If I readbthis right, you have two 9.9s, some bodybtold you those were "upgraded to 20's. Methinks they lied or the upgrade failed and you still have two 9.9's. Not enough real power. 

 

Good luck.